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insidious

adjective

Definition of insidiousnext
as in treacherous
formal causing harm in a way that is gradual or not easily noticed Most people with this insidious disease have no idea that they are infected. an insidious enemy

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Example Sentences

Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Recent Examples of insidious When his insidious nature is revealed, the change in tone and his face gone malformed, the scene feels dynamic in a way that doesn’t require gore or intricate special effects. — Literary Hub, 28 Aug. 2026 The broader opportunity costs of the United States’ Middle Eastern follies are even more insidious. — Emma Ashford, Foreign Affairs, 12 Aug. 2026 However, there is another, slower and more insidious evacuation taking place, and that is the steady migration from rural areas all around the world to burgeoning cities, which now host more than half the world’s population. — John Vaillant, Time, 8 Aug. 2026 This insidious method is a form of bullying, causing significant psychological harm and higher dissatisfaction than overt harassment. — Jason Walker Psyd, Forbes.com, 6 Aug. 2026 See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
  1. treacherous
  2. subtle
  3. perfidious
  4. deceptive
  5. false
  6. misleading
  7. deceitful
  8. incorrect
Adjective
  • International skullduggery in this case concerned the retrieving of two nuclear warheads from a treacherous Caribbean dictatorship.
    — Ed Olmstead, HollywoodReporter, 17 Sep. 2026
  • Bryan, without chains on his tires, drives up a treacherous farm-country road in the snowy night, which lends the movie a fairy-tale atmosphere.
    — Owen Gleiberman, Variety, 16 Sep. 2026
Definition of treacherous
Adjective
  • Rey’s directing style keeps the spirit of Mumblecore cinema while bringing it into the immediate present, injecting subtle political commentary into naturalistic scenes.
    — Jourdain Searles, HollywoodReporter, 16 Sep. 2026
  • In other New York Fashion Week shows, like TWP and Proenza Schouler, fashion’s adjacent garden shoe trend took a more subtle approach.
    — Jaden Thompson, Footwear News, 16 Sep. 2026
Definition of subtle
Adjective
  • Logan Marshall-Green as Melanthius Melanthius is a perfidious goatherd who sides with Antinous.
    — Hannah Abraham, Forbes.com, 18 July 2026
  • This is perhaps the most perfidious practice of this sort of politics.
    — David M. Drucker, Twin Cities, 3 June 2026
Definition of perfidious
Adjective
  • When a system can drop the fourth wall unprompted, ingest its own structural tells and re‑engage with unvarnished candor, the vulnerability shifts from deceptive compliance to authentic resonance.
    — Terry Oroszi, Forbes.com, 15 Sep. 2026
  • López’s attorney sent Rivas and her group a cease-and-desist letter last month, citing trademark infringement and deceptive and unfair trade practices, the letter shows.
    — Sofia Saric, Miami Herald, 9 Sep. 2026
Definition of deceptive
Adjective
  • Patel sued the magazine for defamation that month, seeking $250 million and calling the article false and fabricated.
    — CBS News, CBS News, 16 Sep. 2026
  • Perez Hilton’s family is clearing up some false reports tied to the blogger’s recovery from a self-harm incident that unfolded on TikTok last month.
    — Emily St. Martin, Los Angeles Times, 16 Sep. 2026
Definition of false
Adjective
  • A matter of distance and brightness The stars that compose the Triangle — Vega, Altair, and Deneb — lie at very unequal distances from us, so their apparent brightness can give a misleading impression of their true luminosity.
    — Joe Rao, Space.com, 10 Sep. 2026
  • Publishers don’t want irrelevant or misleading ads to appear on their media sources.
    — Roman Vrublivskyi, Forbes.com, 10 Sep. 2026
Definition of misleading
Adjective
  • Bogus texts, mystery calls, deceitful emails all aimed at stealing your personal information and your money are relentless.
    — Donna Vickroy, Chicago Tribune, 13 Aug. 2026
  • The mutual trust and goodwill that xenia sought to cultivate has been eroded by this one deceitful act, creating a world that is defined by this moral violation.
    — Brianna Zigler, Entertainment Weekly, 19 July 2026
Definition of deceitful
Adjective
  • There is no doubt this one will be chalked up as an incorrect decision in the eyes of the KMI panel.
    — Oliver Kay, New York Times, 15 Sep. 2026
  • Earlier reports that the fire was caused by damage to the Tesla’s lithium-ion battery may be incorrect, Brown said.
    — Haley Parsley, Sacbee.com, 13 Sep. 2026
Definition of incorrect

Browse Nearby Words

inside tracks
insidious
insidiously
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Cite this Entry

“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 19 Sep. 2026.

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